Your first question has been asked before - also see this post. The short answer is that you want to use the cursor returned by find unless you really need all of the data at once in order to manipulate it before sending it to a template.

Your CoffeeScript could be rewritten as:

titles = (entry.title for entry in Entries.find().fetch())

If you are using underscore, it could also be written as:

titles = _.pluck Entries.find().fetch(), 'title'

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